Disease in man can be viewed as a psychophysiologic response that is maladaptive - maladaptive in the sense of a protective reaction that is inappropriate in kind or in magnitude, which then enhances man's vulnerability to illness. In this department, studies investigating this concept have ranged from specific illnesses, such as tuberculosis, cardiovascular diseases, asthma, etc., to investigations of psychosocial readjustments as an important variable underlying all illnesses. Past and ongoing studies have shown that an accumulation of life events is related to onset of illness, but the mechanisms by which the required psychosocial readjustments are transduced into biological systems which act faultily to produce illness symptoms are unknown. This research investigates one aspect of the total overall program. It is the hypothesis of this research proposal that sympathetic lability and adrenocortical responses are factors in the individual's susceptibility to a variety of illnesses, that individuals differ in their labilities, and thus to illness susceptibilities, and that variability of these parameters during the day is related to the variability across days. We propose to investigate the urinary excretion of catecholamine and 17-OHCS metabolites on an intra-day and inter-day basis. Levels of variabilities of these metabolites would be correlated to individual retrospective illness histories and magnitudes. The relationship of daily happenings, mood changes and symptomatic complaints would be related to daily biochemical determinations. A second collection of illness histories as a two-year follow-up would indicate the predictive validity of the physiological variabilities.